JP2004214220A - Induction heating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an induction heating device equipped with a heating coil, whereof a coil resistance with respect to a high frequency current is reduced, by lessening the influence of proximity action of the high frequency current. <P>SOLUTION: This induction heating device is formed by winding a coil wire 16, and is provided with a heating coil to inductively heat an object to be heated. The coil wire 16 is formed by stranding a strand obtained by providing an insulating layer on the periphery of a conductor or aggregate wires formed by bundling the strands, and is also formed by providing an insulating material 17 of a fluororesin having a high melting point in the outer periphery of the coil wire and a fusible layer 22 of a fluororesin having a low melting point in its outside. The heating coil is made by winding the coil wire 16 provided with the insulating material on the outer periphery and by fusing and solidifying the fusible layer 22. Therefore, this induction heating device, whereby the influence of the skin effect and the proximity action is lessen, self-heating of the heating coil is not much, heating efficiency is therefore excellent, and heating adhesiveness is enhanced, can be provided. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to an induction heating device, and more particularly, to a heating coil in which loss due to high-frequency current is reduced.

  Conventionally, an induction heating device can heat only an iron-based metal having a high magnetic permeability. In recent years, however, it has been desired to heat a metal other than iron, such as copper or aluminum. In particular, in an induction heating cooker in which a heating device is applied to a cooker, there has recently been an increasing demand for using a copper pot or an aluminum pot in addition to an iron pot. By the way, in order to induction-heat a copper pan or an aluminum pan, a high-frequency current of 40 to 100 kHz, which is higher than 20 to 30 kHz suitable for an iron pan due to low magnetic permeability, must be passed through the heating coil. However, the higher the frequency, the more the so-called skin effect causes a high-frequency current to flow only near the surface of the conducting wire, so that the effective resistance remarkably increases. Therefore, as a method of increasing the surface area and effectively reducing the resistance, a method has been used in which the diameter of the conductive wire is reduced and, for example, several to several tens of conductive wires having a diameter of 0.1 mm or less are bundled. However, in this method, even if the effective resistance due to the skin effect can be reduced, the proximity effect becomes remarkable due to the use of many conductors, and the resistance cannot always be sufficiently reduced. The term “proximity effect” as used herein refers to a phenomenon in which when a current flows through a close conductor, they mutually affect each other via a magnetic field, causing a bias in the current distribution, and an effective increase in the resistance of the conductor surface. . The proximity effect increases as the direction of the high-frequency current is more uniform between the conductors and the spacing between the conductors is smaller.

As a method for solving the above-mentioned problem, the coil conductor of the heating coil is formed as a multi-stage aggregate structure in which the aggregated wires obtained by bundling the wires are further aggregated, and at least the aggregate wire of one stage is formed by knitting. The orientations of the gathering wires are not uniform and do not adhere to each other, whereby the proximity effect can be suppressed and the coil resistance of the heating coil to high-frequency current can be reduced (for example, see Patent Document 1).
Japanese Patent Publication No. 7-118377

  However, in the above-described conventional configuration, although the coil resistance of the heating coil with respect to the high-frequency current can be reduced, it is necessary to further reduce the coil resistance with respect to the high-frequency current in order to further improve the efficiency of induction heating.

  The present invention solves the above-mentioned conventional problems, and provides an induction heating apparatus that reduces the influence of proximity action, reduces coil resistance of a heating coil against high-frequency current, and has a small self-heating of the heating coil and high heating efficiency. The purpose is to do.

  In order to solve the conventional problem, the induction heating device of the present invention includes a heating coil formed by winding a coil conductor, and the coil conductor includes a wire having an insulating layer provided around a conductor or the wire. Insulation that is formed by twisting bundled bundled wires, and is composed of a fluororesin with a different melting point on part or all of its outer circumference, and a fluororesin with a lower melting point is outside the fluororesin with a higher melting point The heating coil is formed by heating the coil conductor after winding and melting and solidifying the fluororesin formed on the outer side to form the adjacent insulators or the insulator and the element wire. The heating coil is fixed to stabilize the shape, and a high-frequency current of 40 to 100 kHz is applied to the heating coil to heat the object to be heated, such as copper or aluminum, by induction. With this configuration, when a coil is wound using a coil conductor to produce a heating coil, there is an insulator between the coil conductors, so the spacing between the coil conductors is widened, and the increase in high-frequency resistance due to the proximity action between the strands is reduced. It is possible to improve the insulation strength and heat adhesion between coil conductors by using a fluoropolymer with a low melting point on the outside as the insulator and using a fluoropolymer with a high melting point on the inside to melt and solidify the fluoropolymer with a low melting point on the outside. And reliability can be improved.

  ADVANTAGE OF THE INVENTION According to this invention, the influence of the skin effect and the proximity effect can be reduced, and a heating coil having a reduced coil resistance to high-frequency current can be obtained. It is possible to provide an induction heating device in which the heating self-heating of the heating coil is small, the heating efficiency is good, the insulation of the heating coil is stabilized, the heating adhesion is improved, the reliability of the insulation is secured, and the cost is reduced. it can.

  The invention according to claim 1 is provided with a heating coil formed by winding a coil conductor, and the coil conductor is obtained by twisting an element wire provided with an insulating layer around a conductor or an assembly wire obtained by bundling the element wire. While being formed, an insulator made of a fluororesin having a different melting point is provided on a part of or the entire outer periphery thereof, and a fluororesin having a lower melting point is provided outside a fluororesin having a higher melting point, and the heating coil is After winding the coil conductor provided with the insulator, heating and melting and solidifying the fluororesin formed on the outside, the adjacent insulators or the insulator and the element wire are fixed to each other to form a shape. In addition to stabilizing the coil, a high-frequency current of 40 to 100 kHz is applied to the heating coil to inductively heat the object to be heated, such as copper or aluminum. When a wound heating coil is manufactured, the insulation between the coil conductors increases the spacing between the coil conductors, thereby reducing the increase in high-frequency resistance due to the proximity action between the strands, and as an insulator outside. Using low-melting-point fluororesin, inner high-melting-point fluororesin is used to melt and solidify the low-melting-point outer fluororesin, so insulation strength between coil conductors is improved, reliability can be improved, and heating is further improved. The adhesiveness can be improved and the shape of the heating coil can be stabilized.

  The invention according to claim 2 is provided with a heating coil formed by winding a coil conductor, and the coil conductor is formed by twisting an element wire provided with an insulating layer around a conductor or an assembly wire obtained by bundling the element wire. Form an upper assembly line, at least a part or the entire outer periphery of the upper assembly line is provided with an insulator in which a fluororesin having a low melting point is formed outside the fluororesin having a high melting point, and the insulator is provided on the outer periphery. The heating coil is heated after winding the coil conductor on which the insulator is provided, and the fluorocarbon resin formed on the outside is melted and solidified. By stabilizing the shape by adhering the insulators or the insulator and the strand by adjoining each other, a high-frequency current of 40 to 100 kHz is passed through the heating coil to remove the copper. By using a configuration in which a metal to be heated such as aluminum is induction-heated, when a coil is wound using a coil conductor to produce a heating coil, there is an insulator between the upper assembly lines, so the spacing between the upper assembly lines In addition to reducing the increase in high-frequency resistance due to the proximity action between the wires, it is possible to reduce the increase in high-frequency resistance. Due to the presence of the body, the overall insulation strength is improved, the reliability can be improved, and the heat adhesion can be improved, and the shape of the heating coil can be stabilized.

  The invention according to claim 3 is a device in which a high-frequency current is applied to a heating coil formed by winding a coil conductor to heat an object to be heated, wherein the heating coil has a wire volume with respect to its entire space volume. By configuring the conductor volume to be 50% or less, the distance between the wires as a whole of the heating coil is widened, and an increase in resistance due to the proximity action can be suppressed.

  In particular, when the diameter of the conductor portion of the wire is 0.1 mm or less, it becomes difficult to apply a thick insulating layer of the wire itself in terms of manufacturing and the cost increases. Alternatively, by providing an insulator around the outer periphery of the coil conductor, insulation can be easily strengthened, thereby improving reliability and reducing costs.

(Embodiment 1)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings, taking an induction heating cooker as an example of an induction heating device. A feature of the present embodiment is that a coil conductor is manufactured by assembling wires having different cross-sectional areas, and the coil conductor is wound to provide a heating coil. As described above, when a high-frequency current of 40 to 100 kHz is applied to a heating coil to heat a heating body having a low magnetic permeability such as a copper pot or an aluminum pot, the effective resistance of the heating coil increases due to a so-called skin effect. Therefore, in order to reduce the effect of the skin effect, wires with a small cross-sectional area are used, but if wires with a small cross-sectional area are used, the windings are denser, that is, the occupancy is improved, and the The distance is small, and the increase in resistance due to the proximity action becomes remarkable. In the present invention, the skin effect is reduced by using a large number of strands having a small cross-sectional area, and by mixing a strand having a small cross-sectional area with a strand having a large cross-sectional area, a strand having a small cross-sectional area is mixed. The spacing is substantially increased, and an increase in resistance due to proximity action can be suppressed, the high-frequency resistance of the heating coil can be substantially reduced, self-heating of the heating coil can be reduced, and heating efficiency can be improved. . Hereinafter, description will be made with reference to the drawings.

  First, a schematic configuration of the induction heating cooker will be described with reference to FIG. 1 is a main body constituting an outer shell of the induction heating cooker, 2 is a top plate provided on the main body 1, 3 is a heating coil formed by winding using a coil conductor according to the present invention, and 4 is a heating coil 3 is controlled. Reference numeral 5 denotes a heating unit such as a pot placed on a heating unit provided on the top plate 2 corresponding to the heating coil 3. In this configuration, when a high-frequency current flows through the heating coil 3, a magnetic flux is generated, and the heating element 5 is heated by heat generated by eddy current loss of the magnetic flux.

  Hereinafter, the configuration of the coil conductor in the present embodiment will be described. FIG. 1 is a sectional view of an assembly line of a heating coil used in an induction heating cooker according to a first embodiment of the present invention. In FIG. 1, a collective wire 6 is formed by mixing a wire 7 having a small sectional area, for example, a wire having a diameter of 0.05 mm, and a wire 8 having a large sectional area, for example, a wire having a diameter of 0.1 mm. Are bundled or twisted together. In FIG. 1, in order to reduce the proximity effect of the wire 7 having a small sectional area used for reducing the skin effect, the wire 7 having a small sectional area and the wire 8 having a large sectional area are mixed at random. FIG. Thereby, the effective spacing between the strands 7 having a small cross-sectional area can be increased. As described above, when the strands 7 having a small cross-sectional area are always interposed between the strands 8 having a large cross-sectional area so that the spacing between the strands 7 having a small cross-sectional area is effectively increased, the proximity effect is obtained. Can be reduced. Further, it is more effective if the wires 7 having a small cross-sectional area and the wires 8 having a large cross-sectional area are not biased.

  As a first step, the bundles obtained in this manner are twisted in several bundles to form a higher rank collective line, and if necessary, in a second stage, the higher bundles are twisted into several bundles to form a higher-order collective line. When a heating coil is manufactured by winding a coil conductor having a multi-stage ply-twist structure in which a higher-level assembly wire is twisted a plurality of times as described above, the high-frequency resistance of the heating coil increases due to the proximity action even when a high-frequency current of 40 to 100 kHz flows. Can be suppressed, self-heating of the heating coil can be reduced, and a heating coil with good heating efficiency can be obtained. That is, when the cross-sectional area of the wire having a diameter of 0.05 mm and the wire having a diameter of 0.1 mm are made equal by adjusting the number of wires, the high-frequency resistance of the wire having a diameter of 0.05 mm is smaller. Therefore, when a wire with a diameter of 0.05 mm and a wire with a diameter of 0.1 mm are mixed, a high-frequency current mainly flows through the wire with a diameter of 0.05 mm, and the wire with a diameter of 0.1 mm is too small. It stops flowing. Here, the space between the 0.05 mm diameter and the 0.05 mm diameter is expanded by inserting the 0.1 mm diameter wire into the 0.05 mm diameter wire, and the high frequency resistance of the heating coil is increased by the proximity action. Can be prevented.

  FIG. 3 is a sectional view of a collective line of a heating coil showing another example used for the induction heating cooker according to the first embodiment of the present invention. In FIG. 3, a wire 7 having a small cross-sectional area is arranged around a wire 8 having a large cross-sectional area, for example, nine wires of 0.05 mm are arranged around a wire of 0.1 mm. It is twisted as. Further, the collective wires 9 are twisted to form a higher collective wire 10. By doing so, the effective spacing between the strands 7 having a small cross-sectional area can be widened in a well-balanced manner, so that an increase in resistance due to the proximity action can be suppressed in a well-balanced manner. Further, if necessary, the upper assembly wire 10 is twisted to form a higher assembly wire, and this process is repeated as necessary, whereby a coil conductor having a multi-stage lap-twist structure can be obtained.

  FIG. 4 is a sectional view showing an assembly line of another heating coil used for the induction heating cooker according to the first embodiment of the present invention. In FIG. 4, the strand 7 having a small cross-sectional area is a stranded collective wire 12, the strand 8 having a large cross-sectional area is arranged around the stranded collective wire 11, and these are stranded to form a higher collective wire 13. . For example, in the figure, eight bundles of strands each having a small cross-sectional area of 0.1 mm are twisted into four to form a bundle, and seven strands each having a small cross-section of 0.05 mm are twisted around the bundle. It is a high-ranked twisted assembly line. By doing so, the effective spacing between the strands having a small cross-sectional area can be widened in a well-balanced manner, so that an increase in high-frequency resistance due to the proximity action can be stably suppressed.

  In the first embodiment, as shown in FIGS. 3 and 4, a wire having a small cross-sectional area is disposed around a wire having a large cross-sectional area. A wire having a large cross-sectional area may be arranged on the wire. In short, a wire having a small cross-sectional area and a wire having a large cross-sectional area may be arranged in a well-balanced manner.

(Embodiment 2)
The present embodiment relates to a coil conductor having a multi-stage lap-twisted structure constituted by performing a plurality of twisting steps as needed, further twisting a plurality of assembled wires obtained by twisting thin strands, particularly An insulator is provided on at least a part of the coil conductor or the assembly wire to increase the effective distance between the wires and suppress an increase in resistance due to the proximity action. This will be described below with reference to the drawings.

  FIG. 5 is a cross-sectional view of the coil conductor of the induction heating cooker according to the second embodiment of the present invention. In the figure, 7 bundles of bundled thin wires, for example, 60 bundles of wires having a diameter of 0.05 mm, are twisted into 7 bundles, which is referred to as an upper bundle 15, and this upper bundle 15 is further bundled into 3 bundles in a multi-stage stack. The coil conductor 16 has a twisted structure. After applying heat to the coil conductor 16 to reduce volatile components contained in the coil conductor 16 itself, an insulator 17 is provided on at least a part of the outer periphery of the coil conductor 16. When a heating coil is manufactured by winding the coil conductors 16 having this configuration, an insulator is present in at least a part between the coil conductors 16, so that the interval between the coil conductors 16 is increased, and as a result, the interval between the element wires is increased. Is increased, so that an increase in high-frequency resistance due to proximity action can be suppressed. In addition, when an insulator is provided on the entire coil conductor 16, the entire insulation strength between the coil conductors 16 when the coil conductor 16 is wound increases, and the reliability can be improved. Further, since the voltage difference between the turns of the coil conductor 16 is large, as a result, this method of providing the insulator 17 between the turns has high insulation reliability. Further, when the diameter of the wire is about 0.05 mm as in the present embodiment, it is difficult to increase the thickness of the insulating layer of the wire itself in terms of manufacturing, and the cost is increased. Therefore, this method is excellent in securing insulation reliability and realizing cost reduction particularly when a coil wire having a small diameter (0.1 mm or less) is used.

  FIG. 6 is a sectional view showing another coil conductor of the induction heating cooker according to the present embodiment. In FIG. 6, at least a part of the outer periphery of the upper assembly line 15 is covered with the insulator 17 after applying heat to the upper assembly line 15 to reduce the volatile component of the upper assembly line 15 itself. The upper bundle 17 covered with the insulator 17 is twisted into three bundles to form a coil conductor 18. In this configuration, an insulator is present at least in a part between the upper collective lines 15, so that the interval between the upper collective lines 15 is increased, and the interval between the element wires is increased, so that an increase in resistance due to the proximity action is suppressed. can do. In addition, if the coil conductor 18 is manufactured in such a manner that an insulator is provided on the entire upper assembly wire 15, the insulator is present between the coil conductors 18 when the coil is wound, so that the overall insulation strength increases and the reliability increases. Can be increased.

  As a method of providing an insulator on the coil conductor 16, a tape or a thread may be wound around the coil conductor 16, or a film-like insulator may be sandwiched at the time of winding. Alternatively, a method of applying and curing a liquid substance may be used.

  As the insulator, glass fiber or mica is used as an inorganic material having heat resistance, and a tape or film made of a fluorine resin, a polyimide resin, a polyamideimide resin, or the like is used as an organic material. Of these, glass tape is suitable because of its low price and good workability. Further, the glass tape is suitable for impregnating the inside of the resin because the resin penetrates when the shape of the heating coil device is stabilized by impregnating the resin after manufacturing the heating coil.

  As a method of omitting the resin impregnation step, a method using a self-fusion line shown in FIG. 7 is generally performed. That is, a heating coil is produced using a wire provided with an insulating layer 20 around the conductor 19 and further provided with a fusion layer 21 outside thereof, and then the fusion layer 21 is melted and solidified by heating. This is a method in which the wires are fixed so that the shape of the heating coil can be stably maintained.

  In the present embodiment, since an insulator is provided on the outer periphery of the coil conductor or the outer periphery of the upper assembly wire, the shape of the heating coil can be stabilized by using this insulator without using the fusion layer 21 of the strand. Can be kept. That is, a thermoplastic resin such as a polyamide resin, a polyamide-imide resin, a polyester resin, or a fluororesin is used as an insulator, and the thermoplastic resin is heated and melted in the middle of manufacturing a heating coil or after winding the heating coil. By solidifying the insulator, the insulator and the insulator or the insulator and the element wire are fixed, and the shape of the heating coil can be stabilized. Further, by forming the insulator from two kinds of resins having different melting points and forming the resin having a lower melting point outside the resin having a higher melting point, the heat adhesion can be improved. For example, if a fluororesin is used for the insulator, a fluororesin (ETFE or FEP) having a low melting point is used on the outside, and a fluororesin (PFA) having a high melting point is used on the inside, it is possible to improve the stable insulation and the heat adhesion. Can be.

  Furthermore, by using an uncured or semi-cured rubber or a thermosetting resin as the insulator, and heating and solidifying the heating coil in the middle of the manufacturing process or after winding the heating coil, the insulator and the insulator or The shape of the heating coil can be stabilized by fixing the insulator and the wire. Silicone or fluorine rubber is used as the rubber, and epoxy resin, unsaturated polyester resin, phenol resin, or the like is used as the heat effect resin.

  In addition, uncured or semi-cured rubber or resin, particularly semi-cured rubber or resin, is applied or impregnated to a woven or non-woven fabric as an insulator, and heated and cured as described above to stabilize the shape of the heating coil. be able to. In particular, when a tape-shaped woven or nonwoven fabric is used, a part or the whole of the outer periphery of the collecting wire or the coil conductor can be easily wound, so that the handling is easy and a stable insulating layer can be provided. Note that the same type of rubber or resin as described above is generally used.

  Also, as shown in FIG. 8, after applying heat in advance to reduce the volatile components contained in the coil conductor 16 itself, an insulator 17 is provided around the coil conductor 16 and an adhesive layer 22 is further provided outside the insulator 17. It may be. The adhesive layer here includes a fusion layer. After winding the coil conductor 16 having this configuration, the coil conductor is heated to fix the coil conductor and the coil conductor, so that a heating coil having a stable shape can be obtained.

  In addition, a heat shrink tape may be used. That is, after winding the heat-shrinkable tape around the upper collective wire or / and the coil conductor, the tape shrinks by heating, and the upper collective wire or / and the coil conductor is tightened, so that the heating coil can be formed into a stable shape. .

  With the configuration described above, the shape of the heating coil can be stabilized without using the fusion layer of the strand. However, if the fusion layer is not used, the distance between the wires becomes small, and the proximity effect may cause a problem of an increase in resistance. In this case, the thickness of the insulation corresponding to the fusion layer may be increased. This simplifies the manufacturing process of the wire and reduces the cost.

  Note that the heat resistance of the insulating material may be selected from heat resistance categories required by design.

  As described above, according to the present embodiment, it is possible to suppress the increase in the high-frequency resistance due to the proximity action, and to improve the insulation performance and the reliability. Further, by using an insulating structure having adhesiveness, the stability of the coil shape can be achieved. In addition, after the volatile components of the coil conductor and the upper assembly wire are reduced by heat, an insulator is provided around the outer periphery of the coil conductor and the upper assembly wire. When heat is applied to the heating coil at the time of bonding, volatile components generated from inside the heating coil do not accumulate between the upper assembly line and the insulator or between the coil conductor and the insulator. Deformation can be prevented.

  As described in the first and second embodiments, in order to suppress the increase in the high-frequency resistance due to the proximity action, the cross-sectional area of the strand is increased, or the insulator is provided on the upper assembly line or the coil conductor. It is effective to provide them. Therefore, the influence of the proximity action on the entire heating coil was examined by experiments such as changing the cross-sectional area of the wire and changing the thickness and amount of the insulator. As a result, when the insulator is wound around the outer periphery of the heating coil, the cross-sectional area of the insulator that does not include the outer insulator, that is, the insulating layer portion of the element wire with respect to the entire space cross-sectional area occupied by the heating coil. If the configuration is such that the volume of the conductor portion does not exceed 50%, an increase in high-frequency resistance due to proximity action can be suppressed, and if this ratio exceeds 50%, the high-frequency resistance due to proximity action significantly increases. Obtained. As a result, an effect is obtained that the design in consideration of the proximity effect is facilitated.

  The effects of the first and second embodiments are particularly effective when induction heating is performed on an object to be heated such as a copper pan or an aluminum pan with a high-frequency current of 40 to 100 kHz.

  Although the present embodiment has been described using an induction heating cooker as an example of the induction heating device, the same effect can be obtained with other various induction heating devices.

  As described above, the induction heating device according to the present invention can reduce the skin effect and the proximity effect of the high-frequency current in the heating coil, reduce the coil resistance to the high-frequency current, and improve the insulation of the heating coil. It is possible to stabilize and improve the heat adhesion to secure insulation reliability and to further reduce the cost. Therefore, when the object to be heated such as a copper pan or an aluminum pan is induction-heated with a high-frequency current of 40 to 100 kHz, particularly, It is valid.

Sectional drawing of the assembly line of the heating coil used for the induction heating cooker in the 1st Embodiment of this invention Configuration sectional view of the induction heating cooker Sectional view of the assembly line in another example of the heating coil used in the induction heating cooker Sectional view of the assembly line in another example of the heating coil used in the induction heating cooker Sectional drawing of the assembly line of the heating coil used for the induction heating cooker in the second embodiment of the present invention. Sectional view of the assembly line in another example of the heating coil used in the induction heating cooker Cross section of the configuration of the strand Sectional drawing of the assembly line of another example of the heating coil used for the induction heating cooker according to the second embodiment of the present invention.

Explanation of reference numerals

3 Heating coil 6, 9, 11, 12, 14 Assembly wire 7 Element wire with small cross-sectional area 8 Element wire with large cross-sectional area 10, 13, 15 Upper assembly wire 16, 18 Coil conductor 17 Insulator 22 Adhesive layer (adhesive part) )

Claims (4)

A heating coil formed by winding a coil conductor, wherein the coil conductor is formed by twisting an element wire provided with an insulating layer around a conductor or an assembly wire obtained by bundling the element wire; A part or the whole is made of a fluororesin having a different melting point, and an insulator made of a fluororesin having a lower melting point is provided outside the fluororesin having a higher melting point, and the heating coil is heated after winding the coil conductor. By melting and solidifying the fluororesin formed on the outside, the insulators adjacent to each other or the insulator and the element wire are fixed to stabilize the shape, and a high-frequency current of 40 to 100 kHz is applied to the heating coil. And an induction heating device configured to induction-heat an object to be heated of a metal such as copper or aluminum. A heating coil formed by winding a coil conductor is provided, and the coil conductor is formed by twisting an element wire provided with an insulating layer around a conductor or an assembly wire obtained by bundling the element wires to form a higher-order assembly wire, and at least the Provide an insulator in which a fluororesin having a low melting point is formed outside of a fluororesin having a high melting point on a part or the whole of the outer periphery of the upper assembly line, and further twist the upper assembly line provided with the insulator on the outer periphery. The heating coil is formed by winding the coil conductor on which the insulator is provided, and then heating the coil to melt and solidify the fluororesin formed on the outside. Alternatively, the insulator and the strand are fixed to each other to stabilize the shape, and a high-frequency current of 40 to 100 kHz is supplied to the heating coil to form a metal such as copper or aluminum. Induction heating apparatus configured to inductively heat the object to be heated in. The induction heating device according to claim 1, wherein the heating coil is configured such that a conductor portion volume of the element wire is 50% or less of an entire space volume. The induction heating device according to any one of claims 1 to 3, wherein a wire having a diameter of a conductor portion of 0.1 mm or less is used for at least a part of the coil conductor.

Images